Use the Uninstaller in The Sims 3 Applications Folder to uninstall all your Expansion Packs, Stuff Packs and the Base Game. Make sure to back up saved games by following the instructions in How to Backup my Saved Games in The Sims 3.

Leopard/Snow Leopard users

1. Open a Finder window.
2. Click on your Home/User folder (This should be the one with the icon of a house).
3. Open the Library folder in the right-hand pane.
4. Open the Preferences folder.
5. Delete Cider Preferences folder.
6. Delete The Sims 3 Preferences folder.
7. Delete any files that have Trans gaming in the name.
8. Delete any files that have Sims in the name.

 Lion/Mavericks users

1. Open Finder by clicking anywhere on the Desktop or see "Finder" in the menu bar by the Apple logo
2. Click on Go.
3. Hold down Option while clicking the Go menu to reveal additional options.
4. The Library folder will now appear.
5. Open the Preferences folder.
6. Delete Cider Preferences folder.
7. Delete The Sims 3 Preferences folder.
8. Delete any files that have Transgaming in the name.
9. Delete any files that have Sims in the name.
10. Click on the Go menu again and choose Back or see step 3 to return to the Library folder.
11. Open Saved Application State folder.
12. Delete any files that have Transgaming in the name.
13. Delete any files that have Sims in the name.

Find out how to uninstall The Sims 3 on PC.

Learn more information on uninstalling Expansion and Stuff Packs on a Mac.